EVA 4400 and mixed size Disk Group

Posted on 2009-04-21
Medium Priority
Last Modified: 2013-11-14
We have an EVA 4400 with a single shelf containing 8 x 146gb drives.   If we add 4 x 400gb disks in the remaining bays whats the maximum capacity we can get?  Note, we require a decent level of redundancy as the EVA will we be running critical systems.

Question by:kswan_expert
  • 2

Expert Comment

ID: 24202010
if you add new HDs to your Storage, and these are of different size of previous
(400,146) , you cannot add the 400s to any existing array. You have to build
a new array, then split(or take whole) this in LV(s), then LUN(s).
You can build a RAID5 having 400x3GB resultant, or RAID10 (=400x2), or
2 RAID1 (2 x 400).

Does just one server access the storage ?

If you build another Array->Lun, you'll see this as a new disk in server
(which OS ?), partition it(Unix or Win), Format(U/W with diff commands) and
create a new volume (Letter in Win F:) or mount this partition under an existing
directory (in Unix this is the sole possible method) but you can also do this in Win
OS. If you need space on your C: or E: disk, and you know all growing space will
concentrate in a dir, you can move these in anothe location, mount new partition under this dir, re-copy moved files in that dir. Physically the files will go in the new 4x400GBHDs, even OS continues to write undes C:\MyApplication.

LVL 56

Expert Comment

ID: 24202785
You can have mixed drive sizes in an EVA disk group but it's not a good idea since they will have many more disks accesses than the current disks and will therefore becone "hot" disks. re-levelling based on I/O will be competing with re-levelling based on capacity usage. Sparing as well as parity will also eat up the size of the largest disk in the group.

So assuming vRAID5 with a sparing level of one, 146*8 + 400*4 - 400(parity) -400 (spare) = 1968GB (of course occupancy alarm will be going potty by that time as it goes off when there is 15% space left)

Assuming vRAID5 with sparing of two, 146*8 + 400*4 -400(parity) -2*400(spare) = 1568GB.

I'm afraid that what dolomiti says doesn't work since you cannot make a disk group with less than 8 disks on an EVA.

See also this thread, http://forums13.itrc.hp.com/service/forums/questionanswer.do?admit=109447627+1240392856274+28353475&threadId=1116697

LVL 56

Accepted Solution

andyalder earned 1500 total points
ID: 24202859
Oops, knock 400GB off the above calcs, vRAID 5 uses 1 parity for every 8 disks in the disk group so parity will take up 800GB in each case, not 400GB.

Author Comment

ID: 24221669
Cheers Andy.  

Featured Post

Configuration Guide and Best Practices

Read the guide to learn how to orchestrate Data ONTAP, create application-consistent backups and enable fast recovery from NetApp storage snapshots. Version 9.5 also contains performance and scalability enhancements to meet the needs of the largest enterprise environments.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Each year, investment in cloud platforms grows more than 20% (https://www.immun.io/hubfs/Immunio_2016/Content/Marketing/Cloud-Security-Report-2016.pdf?submissionGuid=a8d80a00-6fee-4b85-81db-a4e28f681762) as an increasing number of companies begin to…
Article by: evilrix
Looking for a way to avoid searching through large data sets for data that doesn't exist? A Bloom Filter might be what you need. This data structure is a probabilistic filter that allows you to avoid unnecessary searches when you know the data defin…
This video teaches viewers how to encrypt an external drive that requires a password to read and edit the drive. All tasks are done in Disk Utility. Plug in the external drive you wish to encrypt: Make sure all previous data on the drive has been …
Despite its rising prevalence in the business world, "the cloud" is still misunderstood. Some companies still believe common misconceptions about lack of security in cloud solutions and many misuses of cloud storage options still occur every day. …
Suggested Courses
Course of the Month13 days, 14 hours left to enroll

807 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question